Silicon controlled rectifier device for electrostatic discharge protection

Abstract

An SCR device includes a substrate, a plurality of isolation structures defining a first region and a second region in the substrate, an n well disposed in the substrate, an n type first doped region disposed in the first region in the substrate, a p type second doped region disposed in the second region in the substrate, and a p type third doped region (PESD implant region) disposed underneath the first doped region in the first region in the substrate. The well is disposed underneath the first region and the second region, and the third doped region isolates the first doped region from the well.

1. A silicon controlled rectifier (SCR) device for electrostatic discharge (ESD) protection, comprising:
 a substrate; 
 a plurality of isolation structures disposed in the substrate, the isolation structures defining a first region and a second region in the substrate; 
 a well of a first conductive type disposed in the substrate, wherein the well is disposed underneath the first region and the second region; 
 a first doped region of the first conductive type disposed in the first region in the substrate; 
 a second doped region of a second conductive type disposed in the second region in the substrate; and 
 a third doped region of the second conductive type disposed underneath the first doped region in the first region in the substrate, wherein the third doped region isolates the first doped region from the well and is in contact with said isolation structures. 
 
     
     
       2. The SCR device of  claim 1 , wherein the whole third doped region is disposed over the well. 
     
     
       3. The SCR device of  claim 1 , wherein the third doped region partially overlies the well, and partially overlies the substrate. 
     
     
       4. The SCR device of  claim 1 , wherein the substrate has the second conductive type. 
     
     
       5. The SCR device of  claim 1 , further comprises an anode electrically connected to the second doped region, and a cathode electrically connected to the first doped region. 
     
     
       6. The SCR device of  claim 5 , further comprising a fifth doped region of the first conductive type in the second region, the fifth doped region being electrically connected to the anode. 
     
     
       7. The SCR device of  claim 1 , wherein the first doped region is heavily doped. 
     
     
       8. The SCR device of  claim 1 , wherein the second doped region is heavily doped. 
     
     
       9. The SCR device of  claim 1 , wherein the third doped region is heavily doped. 
     
     
       10. A silicon controlled rectifier (SCR) electrostatic discharge (ESD) protection device, comprising:
 a substrate; 
 a plurality of isolation structures disposed in the substrate; 
 a gate structure disposed on the surface of the substrate, the gate structure and the isolation structures defining a first region and a second region in the substrate; 
 a well of a first conductive type disposed in the substrate, wherein the well is disposed underneath the first region and the second region; 
 a first doped region of the first conductive type disposed in the first region in the substrate; 
 a second doped region of a second conductive type disposed in the second region in the substrate; 
 a third doped region of the second conductive type disposed underneath the first doped region in the first region in the substrate; and 
 a fourth doped region of the second conductive type disposed alongside the first doped region, wherein the third doped region and the fourth doped region isolate the first doped region from the well. 
 
     
     
       11. The SCR device of  claim 10 , wherein the whole third doped region is disposed over the well. 
     
     
       12. The SCR device of  claim 10 , wherein the third doped region partially overlies the well, and partially overlies the substrate. 
     
     
       13. The SCR device of  claim 10 , wherein the substrate has the second conductive type. 
     
     
       14. The SCR device of  claim 10 , further comprises an anode electrically connected to the second doped region, and a cathode electrically connected to the first doped region. 
     
     
       15. The SCR device of  claim 14 , further comprising a fifth doped region of the first conductive type in the second region, the fifth doped region being electrically connected to the anode. 
     
     
       16. The SCR device of  claim 10 , wherein the first doped region is heavily doped. 
     
     
       17. The SCR device of  claim 10 , wherein the second doped region is heavily doped. 
     
     
       18. The SCR device of  claim 10 , wherein the third doped region is heavily doped. 
     
     
       19. The SCR device of  claim 10 , wherein the fourth doped region is heavily doped.